A 21-year-old Hispanic woman presented with a 2-year history of an enlarging draining tumor in the right popliteal fossa. She reported that the lesion had begun as a small papule that had remained stable for several months. Rapid growth ensued when she became pregnant. She had immigrated to the United States from Mexico 1 year before her symptoms began, and she denied a history of trauma or unusual bites. She had no constitutional symptoms and was otherwise healthy.
Examination revealed an 8×5-cm, firm, erythematous, hyperpigmented tumor studded with several papules, pustules, and draining sinus tracts (Figure 1). There was no inguinal lymphadenopathy. The patient's initial wound cultures were positive for Acinetobacter organisms, and she had received a 10-day course of erythromycin, without improvement. A skin biopsy was performed. Microscopic features of the specimen are shown in Figure 2 and Figure 3.
Soroush V, Kanzler MH. A Draining Tumor in the Popliteal Fossa. Arch Dermatol. 1999;135(8):983-988. doi:10-1001/pubs.Arch Dermatol.-ISSN-0003-987x-135-8-dof0899